1. Field of the Invention
This invention relates to improvements in valves and more particularly, but not by way of limitation, to a casing overflow vent valve.
2. Description of the Prior Art
It is frequently desirable to vent air or other gaseous fluids from a flow line system, or the like, in order to prevent air pockets in the line which might restrict fluid flow therethrough. In addition, it may be desirable to vent air or gaseous fluids in other environments, such as the casing of a producing oil and/or gas well bore, or the like. Of course, it is desirable to vent the air or gas at these environments without loss of fluid from the system. One type of valve which has been devised to solve this problem is an overflow vent valve manufactured by Baird Manufacturing Company and which comprises a housing adapted to be installed in the line, or the like whereby the interior of the housing is in communication with the interior of the flow line. An internal ported cage is provided in the housing for direction any gaseous fluid present in the flow line to a relief valve provided in the housing. Any pressure present in the flow line which is in excess of atmospheric pressure, or the ambient pressure surrounding the housing will open the valve for venting of the gaseous fluid therethrough. This valve has certain disadvantages in that the valve closure member may be "sucked up" in a manner which might shut the valve during a high-velocity gas flow.